1. Field of Invention
The present invention relates to a vehicle lamp assembly, and to vehicle bulb shield components, and more specifically to a vehicle bulb shield component of a lamp assembly which includes a thermoionic device to improve the energy efficiency of the vehicle headlamp assembly.
2. Background of the Related Art
Thermoionic devices and thermal diodes employ the combination of two semiconductor materials to convert heat into electricity. Recent advances in such devices have realized levels of efficient heat to electrical power conversion as high as 18%, at temperatures between 200 and 300 degrees centigrade. These devices are based on two semiconductors fixed to opposite sides of a barrier layer. One of the semiconductor materials is doped so it is electron rich while the other is depleted of electrons. When installed into an environment where the electron rich semiconductor is a warmer temperature than the temperature of the electron depleted semiconductor, an electrical power flow can be produced. The amount of electrical power produced is related to the difference in temperature between the two semiconductors. A wire lead from each semiconductor serves as the conduit for this electrical power.
Vehicle headlamps are generally comprised of a light source or bulb, an optical reflector, a lens, and in some instances a bulb shield. The purpose of the bulb shield is to control the headlamp light output. To control headlamp output, the bulb shield is placed in close proximity to the headlamp light bulb and therefore reaches temperatures between 200 ad 300 degrees centigrade. Convection of heat from the headlamp light bulb, and bulb shield produces areas of elevated temperature in the headlamp assembly, primarily the areas directly above the light bulb and shield.
The present application provides an improved vehicle headlamp assembly which incorporates thermoionic devices into headlamp assemblies to allow the headlamp to function with a significantly lower draw on the vehicle's electrical power system, which reduced electrical power requirement improves the overall energy efficiency of the vehicle headlamp assembly and the vehicle.